The interaction between gravity waves and solar tides: Results from 4-D ray tracing coupled to a linear tidal model

The interaction between solar tides (STs) and gravity waves (GWs) is studied via the coupling of a three‐dimensional ray tracer model and a linear tidal model. The ray tracer model describes GW dynamics on a spatially and time‐dependent background formed by a monthly mean climatology and STs. It doe...

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Vydané v:Journal of geophysical research. Space physics Ročník 120; číslo 8; s. 6795 - 6817
Hlavní autori: Ribstein, B., Achatz, U., Senf, F.
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: Washington Blackwell Publishing Ltd 01.08.2015
Predmet:
Background radiation
Climatology
Dynamics
Fluxes
Gravitational waves
gravity wave
Gravity waves
Internal waves
Iterative methods
Joining
Mathematical models
mesosphere lower thermosphere
Parametrization
Planetary waves
Primitive equations
ray tracer
Ray tracing
solar tide
Solar tides
Stationary planetary waves
Tidal dynamics
Tides
Tracers
ISSN:2169-9380, 2169-9402
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Popis
Shrnutí:The interaction between solar tides (STs) and gravity waves (GWs) is studied via the coupling of a three‐dimensional ray tracer model and a linear tidal model. The ray tracer model describes GW dynamics on a spatially and time‐dependent background formed by a monthly mean climatology and STs. It does not suffer from typical simplifications of conventional GW parameterizations where horizontal GW propagation and the effects of horizontal background gradients on GW dynamics are neglected. The ray tracer model uses a variant of Wentzel‐Kramers‐Brillouin (WKB) theory where a spectral description in position wave number space is helping to avoid numerical instabilities otherwise likely to occur in caustic‐like situations. The tidal model has been obtained by linearization of the primitive equations about a monthly mean, allowing for stationary planetary waves. The communication between ray tracer model and tidal model is facilitated using latitude‐ and altitude‐dependent coefficients, named Rayleigh friction and Newtonian relaxation, and obtained from regressing GW momentum and buoyancy fluxes against the STs and their tendencies. These coefficients are calculated by the ray tracer model and then implemented into the tidal model. An iterative procedure updates successively the GW fields and the tidal fields until convergence is reached. Notwithstanding the simplicity of the employed GW source, many aspects of observed tidal dynamics are reproduced. It is shown that the conventional “single‐column” approximation leads to significantly overestimated GW fluxes and hence underestimated ST amplitudes, pointing at a sensitive issue of GW parameterizations in general. Key Points Middle atmosphere solar tides and internal gravity waves interaction is analyzed A 4‐D ray tracer model is coupled to a linear tidal model Conventional parameterization leads to overestimated gravity wave fluxes
Bibliografia:ark:/67375/WNG-PZN248XJ-M
Middle Atmosphere in Climate (ROMIC) - No. 01LG1220A
istex:DC955A3FA747533BB092C604D3CF6A1609871DD6
Multiscale Dynamics of Gravity Waves (MS-GWaves) - No. AC 71/8-1; No. AC 71/9-1; No. AC 71/10-1
ArticleID:JGRA51946
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
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ISSN:2169-9380
2169-9402
DOI:10.1002/2015JA021349